Diagnostic Algorithm for Residual Pain After Total Knee Arthroplasty

Area of Science:

• Orthopedics
• Pain Management
• Biomedical Engineering

Background:

• Total knee arthroplasty (TKA) is a common procedure, yet up to 50% of patients report dissatisfaction.
• Postoperative residual knee pain, particularly anteriorly, is a primary driver of dissatisfaction after TKA.
• Patellar resurfacing is included in this review due to the association between un-resurfaced patellae and residual pain.

Purpose of the Study:

• To review the diverse etiologies of residual anterior knee pain after total knee arthroplasty (TKA) with patella replacement.
• To summarize current literature on the causes of persistent pain following TKA.
• To present a diagnostic algorithm to aid in identifying the source of residual knee pain.

Main Methods:

• Literature review of registry data and studies focusing on TKA with patella replacement.
• Analysis of reported causes of residual knee pain, ranging from common to rare etiologies.
• Synthesis of information to develop a practical diagnostic pathway.

Main Results:

• Identified common causes of anterior knee pain post-TKA including infection, instability, malalignment, and maltracking.
• Highlighted less frequent causes such as crepitation, patellar clunk syndrome, overstuffing, avascular necrosis, aseptic loosening, metal hypersensitivity, and pseudoaneurysm.
• Noted that 10-15% of patients may experience unexplained residual pain even after thorough investigation.

Conclusions:

• Residual anterior knee pain after TKA is multifactorial, posing a diagnostic challenge.
• A systematic diagnostic approach, potentially including advanced imaging or injections, is crucial for identifying pain sources.
• Understanding the various etiologies can improve patient outcomes and satisfaction following total knee replacement.